Gummed sheet material



Dec. l2, 1944- c. w. STILLWELL 2,365,020

GUMMED SHEET MATERIL Filed Jan. 15', 1943 PHP5/P anc/mm Paanied Dec. 12, 1944 GUMMED SHEET MATERIAL qharles W. Stillwell, Framingham, Mass., as-

signer to Dennison Manufacturing Company, Framingham, Mass., a corporation of Massachusetts Application January 13, 1943, Serial No. 472,285

24 Claims.

'I'lriis invention relates to the art of gummed sheet material, particularly gummed paper, that is paper coated with normally dry gumming, and the problem of producing such sheet material which does not curl when drying. Since the early development of gummed paper this curling has continued to be a troublesome problem and as evidence that it has not been solved, it is a fact that `up to the present time manufacturers have had to break" the gumming after drying, as for example by drawing the paper over an edge sharply to bend the paper, thereby breaking the gum coating into very small sections along a network ofV cracks. This problem is particularly troublesome in the case of paper and other sheet material wetted by water because of the curling which results from forces set up when the fibers of the material are wetted ain? dried in the process of coating the mater a The principal object of the present invention is to produce gummed sheet material which has little or n'o tendency to curl when drying and which therefore need not be broken after drying. Other objects are to produce gummed sheet material which can be rendered adhesive by wetting with water, thereby .avoiding the use of special moistening agents, which can be rolled or stacked sheet upon sheet without blocking, that is without superposed layers sticking together, which has quick tack when moistened with water, and which has a wide range of adhesion so that it can be satisfactorily applied to many difrerent kinds of surfaces including moistureproof Cellophane.

According` to the present invention, the sheet material is coated on one side with a liquid mixture of Water-soluble adhesive and deformable iiller, with the adhesive in' continuous phase and the filler in discontinuous phase, and the coating is dried, after which the gummed stock may be rolled or stacked Without blocking. Preferably the coating is dried at room temperature, the paper being held flat during the cryingA yoperation. A 4diagrammatic illustration of the product is shown in the accompanying drawing. To stick a gummed sheet to a surface the coating is wetted with water andpressed against the surface like an ordinary gummed label, thus the dry coating is water-activatable.

The preferred water-soluble adhesive is glue or dextrin or a mixture of the twobut any ma'- terial or mixture of materials which becomes tacky when moistened with water may be used, such as gum arabic, some converted starches and certain water dispersible resins such as polymethacrylic acid. The deformable illler comprises resinoids or resinous bodies such as rubber or rubber-like materials, gutta-percha or balata, polymethacrylic esters, either unmodied or modified with other materials such as a plasticizer, in contradistinction to greasy, fatty or oily materials, such as tallow. The deformable ller vshould be elastoplastic, comprising bodies which are elastic, that is, which have a substantial tendency to resume their original shape when deformed and which are generally compressible, or bodies which .are plastic, that is, which do not have the aforesaid tendency and which are generally non-compressible, or bodies which are elastic under some conditions and plastic under other conditions, for example, which react elastically when deformed for av short time but which lose their tendency to resume their original shape -when deformed for a long time. The filler should also be one which can be colloidally dispersed in water without the particles thereof undergoing any appreciable swelling.

'I'he rate at which the'aforesaid curling tend ency decreases with increasing proportions of a particular iiller, which may be referred to as the atness characteristic of the filler, depends on various factors such as the size of the filler particles, the evenness of distribution of the particles-throughout the continuous-phase adhesive, etc., but other factors being equal the iiatness characteristics of the plastic and elastic fillers, as well as their quick-tack and range-of-adhesion characteristics, are markedly superior to those of non-deformable fillers. The deformable iiller preferably comprises latex, rubber or other elastic material but may comprise a natural or synthetic resin or a resinous material to which a suitable plasticizer has been added or a mixture of two or more of any of these materials. While vulcanized latex or vulcanized rubber may be used, the flller is preferably tacky so that after the water-soluble adhesive is moistened the filler contributes to the tackiness of the moistened coating. As is well known rubber may be rendered very tacky by extensive milling -or mastication and latex may be made tacky by basic acid-polyhydric alcohol resins (glyptals), soit Bakelites, gutta-percha resinsor other natural resins with or without plasticizers, mixtures of nitrocotton with blown castor oil, soft Bakelites, etc., mixtures of chlorinated rubber with dibutyl phthalate, soft glyptals, etc., mixtures of rubber with Hercolyn (the methyl ester of hydrogenated abietic acid), ethyl benzoate, decalin, etc., mixtures of normal latex with emul sions of tacky resins such as gutta-percha resin, etc. For certain other 'purposes the following non-tacky fillers are preferable: normal latex, unmilled rubber, synthetic rubber or rubber-ilke materials such as Neoprene (polymer-ized 2-chlorbutadiene), Thiokol (polyethylene vpolysuliide), Buna S (copolymer of butadiene and styrene), etc., andmixtures of film-forming materials with plastic resins in insuicient proportions to render the mixtures tacky, such as mixtures of nitrocotton with acryla' or methacrylate resins of medium or low degree of polymerization such as acryloid resins.

Typical examples of the principal kinds of deformable iillers may be classiiied as follows:

Taeku fillers Plastic- Soft alkyd-resins, soft Bakelites, soft cumars, soit natural resins -such as those from gutta-percha, balata, gutta siak, etc., and mixtures of these with plasticizers, mixtures of hard synthetic or natural resins with plasticizers, mixtures of nitrocotton with blown castor oil or soft Bakelites or soft alkyds, etc.

Plastic or clastic.-Alkyd resins of the type believed to be partially polymerized; e. g., Petrex A'IHt, completely blown and oxidized castor oil, soft acrylate and methacrylate resins, and gums, such an pontianick, guttas, as gutta-percha,

gutta slak, balatas of high resin content, urea-- formaldehyde-alkyd resin mixtures, and polymerized terpenes such as Bexin.

Elastic-Rubber, broken down or mixed with resins, natural or wild rubber, such as Guayule, balatas of low resin content, concentrated solutions of rubber in solvents such as ethyl benzoate, decalin or other high boiling solvents, solutions of rubber plasticized with Hercolyn, mixtures of latex and emulsions of tacky, elastic or plastic such as ammonia or sodium hydroxide in the adhesive, also has a beneficial effect on certain fillers, such as latex. Typical examples of organic solvents are butyl cellosolve, ethylene chlorohydrin, methyl isobutyl ketone, diacetone alcohol and butyl lactate.

To produce a gummed sheet'l which has good non-curling, non-blocking and quick-tack characteristics the dry coating may comprise approximately one-quarter to three-quarters adhesive but a ratio of water-soluble adhesive to filler of approximately two to three is recommended. The following formula is particularly satisfactory because the resulting gumming not only lies substantially iiat over a wide range of relative humidities, but also when remoistened, will adhere satisfactorily on an unusually wide range of surfaces of dierent kinds.

Parts aqueous solution) of high viscosity dextrine, or a mixture oi equal parts oi high viscosity and medium or low viscosity Tacky latex (50% solids) plain or vulcanized 62.5

Concentrated ammonia 2 Another preferred embodiment of the invention results from a mixture of the following compositions A and B in the ratio of 3 to l.

Butyl cellosolve (the mono ethyl ether of ethylene glycol) Parts (One-half second) nitrocottom 20 Rezyl 12-H (a glycerine phthalic anhydride modied with non-drying fatty acid) 15 Tricresyl phosphate 5 Blown castor oil 30 Ethyl acetate 30 Butyl acetate 10 Benzol 20 resins, such.as gutta-percha resin emulsions,

alkyd resin emulsions, gum elemi resin emulsions and rosin emulsions.

Non-tacky fillers Plastic o1' elastic.-Polybutyl methacrylate resins, blown asphalts and pitches.

Elastic- Rubber without much if any milling or processing, and synthetic rubber or rubber-like materials, such as Neoprene, Buna, Thiokol, etc. In producing gummed sheets for application to a particular surface the water-soluble adhesive best suited to that material should be employed and other materials may be added to the glue to improve the adhesive. For example, in producing gummed labels for application to moisture-proof cellophane, the glue may iirst be dissolved in Trigamine (a, commercial substitute for triethanolamine made by Glycol Products Co., New York city);following this, thevusual dispersion with a illler is prepared. This particular mixture is useful in forming a water remoistenable adhesive which willl adhere to the waxy, pyroxylin surface of moisture-proof cellophane. On the other hand the range of materials to 'which the gummed sheets will adhere satisfac- For gummed sheets to be applied to moistureproof Cellophane I recommend a ratio of adhesive to ller of approximately 1 to 2, the following being particularly good formulae:

Parts 30% solution of glue in Trigamine 50 vulcanized latex (50% solids) 60 Concentrated ammonla l 1 part of A mixed with 5 parts of B:

10% emulsion of milled it'iubber in 2% soap lolu- Glue Chloroacctlc acid Ethylene chlorohy drin- To produce si of approximately 1 to 4 as ing formula:

Parts (50% aqueous-high viscosity) dextrine 6 Soft resin emulsion (50% solids) 8 Paraiin wax emulsion (10% solids) 15 Vulcanized latex (50% solids) 15 Concentrated ammonia 1 A gummed sheet which, after being remoistened with water, adheres well to a surface similarly gummed may be prepared according to the following formula: A

` (6) I Parts (50% aqueous highlysoluble) dextrine 15 Very tacky latex' (50%v solids) 40 According to this invention the continuous' phase of the coating may also comprise, as a third component, a water-,soluble plasticizer such as the following: Polyhydric alcohols such as glycerol,'

sorbitol, mannitol; glycols; e, g., ethylene glycol, diethylene glycol, 2'-methyl-2, 4 pentanediol; polyglycols, e. g., Carbowax, Igepal; diand triethanolamine; water-dispersible derivatives of above, such as glyceryl laurate, triacetate (triacetin), diacetate (diacetin) borate, stearate, diethylene glycol stearate, triethanolamine lactate,

abietate, anhydrosorbitols and mannitols, e. g.,

Sorbitan, Mannitan, Mannitan laurate; salts and esters of hydroxy acids, e. g., sodium lactate, ethyl phosphate; triethyl citrate, tricarbitol citrate; amino-alkanols, e. g., 2-amino-2-ethyl-1, 3-propanediol; ether and keto alcohols, e. g., methyl diacetone ether, benzyl ether of ethylene glycol (benzyl cellosolve) mixtures of some of the above with acids and salts such as urea, methyl urea,`

urethane, ammonium thiocyanate. For example, mixtures of glycerine with urea or ammonium thiocyanate plasticizer casein or glue or any other similarprotein more eiectivey and at lower cost than glycerine alone.

In the three-component coatings the adhesive may varybetween approximately one-fourth and three-fourths of the total, the iller may cornprise any proportion from to about 75%, that is less than approximately three-quarters of the total, and the plasticizer may comprise from 0% to about 50%, that is less than approximately one-half of the total, depending on the particular plasticizer employed and how much if any iller is employed', the proportions of plasticizer and ller varying inversely with each other. If less than approximately one-fourth of adhesive is employed, the coating does not have suilicient tack and adhesiveness, and if more than approximately three-quarters adhesive is employed the coated material tends to become substantially curly. If more than approximately three-quarters ller is employed the coating does not have quick tack; and if too much plasticizer is employed the coated material tends to block when the relative humidity exceeds approximately 65%. The range of proportions of the adhesive, plasticizer and ller is defined approximately by the triangular chart boundaries extending along the 75% adhesive line from the plasticizer base line to the filler base line, thence along the ller base line to the 50% plasticizer line, thence along the 50% plasticizer line to the 25% adhesive line, thence along the 25% adhesive line to the plasticizer base line, and thence along the plasticizer base line to the 75% adhesive line.

'I'hus the coated material may comprise not only mixtures of adhesive and filler, as exemplified by the foregoing examples, but also mixtures of adhesive and plasticizer and mixtures of adhesive, plasticizer and filler. The following are exam- 5 ples of mixtures comprising plasticizer in continuous phase. i

Per cent High viscosity dextrine- 40 Sorbitan 25 Latex (60% solids) 35 'Per cent Medium high viscosity animal glue 35 Diacetine 40 Latex (60% solids) 25 Per cent 20. Low viscosity animal glue 55 Glycerylmonostearate 15 Latex (60% solids) 30 Per cent Low viscosity animal glue 25 Triacetin e 25 Latex (60% solids) 50 .so l Per cent Low viscosity animal glue 60 Methyl diacetone ether RHoplex B-10 (solids 25% dispersion in wa-ter of methacrylate polymer) 10 Per cent Gum arabic 30 High viscosity dextrine'.

40 Diethylene glycol monostearate 45 RHoplex WG-6 (solids) (40% dispersion in water of methacrylate-vinyl acetate copolymer) 10 Per cent Low viscosity animal glue 35 Igepal CTA RHoplex WG-G (solids) (40% dispersion in water of methacrylate-vinyl ac'etate copoly- 50 mer 15 (14) Per cent Medium high viscosity animal glue 25 2amno, 2-ethyl, 1-3 propanediol 10 5 Latex (60% solids) 65 Per cent Medium viscosity glue Sorbitan 35 Percent Low viscosity glue f 60 Diacetin 40 (In l v Parts Emulsion TM-8 (urea formaldehyde alkyd m i x t u r e s manufactured by Rohmand u Haas) 24.5

Sodium resinate 46.5 Low lviscosity animal glue 29 From the foregoing it will be evident that each of the illustrative embodiments of the invention comprises gummed sheet material characterized by a dry adhesive in continuous phase and a deformable ller in discontinuous phase, the adhesive comprising approximately one-fourth to three-fourths of the coating, and the product being non-adhesive and substantially non-curling when dry, whereby sheets of the material do not block when stacked together and have quick tack when wetted with water; and the remaining proportion may comprise either filler or plasticizer or va mixture of the two. By using a tacky ller large' proportions of iiller may be used while maintaining quick tack.

It should be understood that the present disclosure is for the purpose of illustration only and that this .invention includes all modifications and equivalents which fall within the scope of the appended claims.

This is in part a continuation of application Serial No. 220,575, iiled July 21, 1938.

I claim:

l. Gummedfsheet material of the water-remoistenable type comprising a backing and on one side of the backing an exposed dry coating of water-activatable adhesive in continuous phase and a deformable resinoid filler in discontinuous phase, the ratio of adhesive to iiller being approximately two to one.

2. Gummed sheet material of the water-remoistenable type comprising a backing and on one side of the backing an exposed dry coating of water-activatable adhesive in continuous phase and a deformable resinoid filler in discontinuous phase, the ratio 'of adhesive to filler being approximately one to two.

3. Gummed sheet material of the water-remoistenable type comprising a backingV and on one side of the backing an exposed dry coating of water-activatable adhesive in continuous phase and a deformable resinoid filler in discontinuous phase, .the ratio of adhesive to iiller being approximately threeto two.

4. Gummed sheet material ofgthe water-reev moistenable type comprising a backing and on one side of the backing an exposed dry coating of water-activatable adhesive in continuous phase and a deformable resinoid filler in discontinuous phase, the adhesive comprising approximately one-fourth to three-fourths of the coating, said material being non-adhesive and substantially non-curling when dry, whereby sheets of the 'material do not block when stacked together and do not curl when separated from each other and have quick tack when wetted with water.

5. Gummed sheet material of the water-remoistenable type comprising a backing and on .one side of the backing an exposed dry coating of water-activatable adhesive in continuous phase and a normally tacky deformable resinoid filler do not block when stacked together and do not curl when separated from each other and have quick tack when wetted with water.

'1. Gummed sheet material of the water-remoistenable type comprising a paper backing and on one 'side of the backing an exposed dry coating of water-activatable adhesive in continuous phase and a normally tacky deformable resinoid ller in discontinuous phase, the adhesive comprising approximately two-thirds of the coating, said material being non-adhesive and substantially non-curling lwhen dry, whereby sheets of the material do not block when stacked together and do not curl when vseparated from each other and have quick tackwhen wetted with water.l

8. Gummed sheet material of the water-remoistenable type comprising a `paper backing and on one side of the backing an exposed dry coating of water-activatable adhesive in con-I tinuous phase and a latex iillerin discontinuous l phase, the adhesive comprising approximately one-fourth to three-fourths of the coating, said material being non-adhesive and substantially non-curling when dry, wherebysheets of the material do not block when stacked together and do not curl when separated from each other and have quick tack when wetted with water.

9. Gummed sheet material of the water-remoistenable type comprising a paper backing and on one side of the backing an exposed dry coating of water-activatable adhesive in continuous phase and a normally tacky rubber filler in discontinuous phase, the adhesive comprising approximately two-thirds of the coating, said .material being non-adhesive and substantially non-curling when dry, whereby sheets of the material do not block when stacked together and do not curl when separated from each other and have quick tack when wetted with water.

10. Sheet material of the character described comprising a backing and on one side of the backing an exposed coating of dry adhesive in continuous phase containing a plastic resinoid filler in discontinuous phase, the adhesivecomprising approximately one-fourth to three-fourths o! the coating.

11. Sheet materialy of the character described comprising a backing and on one side of the backing an exposed coating of dry adhesive in concontaining an elastic resinoid iiller the adhesive comprising tinuous phase in discontinuous phase,

f approximately onefourth to three-fourths of the in discontinuous phase, the adhesive comprising approximately one-fourth to three-fourths of the coating, said material being non-adhesive and substantially non-curling when dry, whereby sheets of the materialdo not block when stacked together and ,do not curl when separated from each other and'have quick tack when wetted with water.

6. Gummed sheet material of the water-remoistenable type comprising a paper backing and on one side of the backing an exposed dry coating of water-activatable adhesive in continuous phase and a deformable resinoid nller in discontinuous phase, the adhesive comprising approximately two-thirds of the coating, saidmaterial being non-adhesive and substantially non-curling when dry, whereby sheets of the material coating.

12. Sheet material' of the character described comprising a backing having an exposed coating of dry adhesive in continuous phase containing a plastic nller in discontinuous phase, the adhesive comprising approximately one-fourth to three-fourths of the coating, said material being non-adhesive and substantially non-curling when dry, whereby sheets of the material do not block when stacked together and do not curl when separated from each other and have quick tack when wetted with water.

13. Sheet material of the character described comprising abacking of dry adhesive in continuous phase containing discontinuous phase. the adhesive comprising approximately one-fourth to block when stacked together and do not curl having an Aexposed coating when separated from each other and have quick tack when wetted with water.

14. A gummed sheet of the character described comprising a backing and a coating of waterremoistenable adhesive in continuous phase and, in discontinuous phase throughout the coating, a deformable resinoid illler-to render the sheet substantially non-curling, said coating being hard to resist blocking and water-activatable to `aiord quick tack when remoistened with water, the adtially non-curling, the adhesive comprising approximately one-fourth toAthree-fourths of the coating.

16. Gummed sheet material of the water-remoistenable type comprising a backing and on one side of the backing an exposed dry coating of water-activatable adhesive and a water-soluble plasticizer in continuous phase and an elastoplastic resinous filler in discontinuous phase, the adhesive comprising approximately onefourth to three-fourths of the coating, the plasticizer comprising less than approximately half of the coating and the iiller comprising less than approximately three-fourths of the coating, said material being non-adhesive and substantially non-curling when dry so that sheets ofthe material do not block when stacked together and do not curl when separated from each other and have quick tack when wetted with water.

17. Gummed sheet material of the waterwemoistenable typecomprising a backing and on one side of the backing an exposed dry coating of water-activatable adhesive and a water-soluble plasticizer in continuous phase and a normally tacky elastoplastic resinous ller in discontinuous phase, the adhesive comprising approximately one-fourth to three-fourths of the coating, the plasticizer comprising less than approximately half of the coating and the'flller comprising less than approximately three-fourths of `the coating, said material being non-adhesive and substantially non-curling when dry so that sheets of the material do not block when stacked together and do not curl when separated from each other and have quick tack when wetted with water.

18. Gummed sheet .material of the water-relmoistenabie type comprising a backing and on one side of the backing an exposed dry'coating oi water-activatable adhesivey and a water-soluble plasticizer in continuous phase anda rubber flller in discontinuous phase, the adhesive comprising approximately one-fourth to v threefourths of the coating, the plasticizer comprising less than approximately half of the coating and the iiller comprising less than approximately three-fourths of the coating, said material being non-adhesive and substantially non-curling when dry so that sheets of thel material do not block when stacked together and do not curl when separated from each other and have quick tack when wetted with water.

19. Gummed sheet material of the water-remoistenable type-comprising a backing and on one side of the backing an exposed dry coating of water-activatablfe.` adhesive and a water-soluble plasticizer in continuous phase and a latex ller in discontinuous phase, the adhesive comprising approximately one-fourth y to threefourths of the coating, the plasticizer comprising less than approximately half of the coating and the ller comprising less than approximately three-fourths of the coating, said material being non-adhesive and substantially non-curling when dry so that sheets of the material do not block when stacked together and do not curl when separated from each other and have quick tact when wetted with water.

I the adhesive, plasticizer and ller 20. A gummed sheet of the character described comprising a backing and a coating of waterremoistenable adhesive and a water-soluble plasticizer in continuous phase and an elastoplastic resinous filler in discontinuous phase throughout the coating, the adhesive comprising approximately one-fourth to three-fourths of lthe coating, -the plasticizer comprising less than approximately half of the coating and the iiller comprising less than approximately three-quarters of the coating, the range of proportions of being defined by the triangular chart boundaries extending along the 75% adhesive line from the plasticizer base line to the filler base line, thence along the ller base line to the 50% plasticizer line, thence along the 50% plasticizer line to the 25% adhesive line, thence` along the 25% adhesive line to the plasticizer baseline, and thence alongthe plasticizer base line to the 75%- adblocking and backing an exposed coating nsl ticizer comprising fter-soluble plasticizer hesive line, said coating being hard to resist water-activatable to afford quick tack when remoistened with water and substantially non-curling.

21. Gummed sheet material of the water-remoistenable .type comprising a paper backing and on one side of the backing an exposed dry coating of water-activatable adhesive and plasticizer in continuous phase and a normally tacky elastic resinoid ller in discontinuous phase, the

adhesive comprising approximately two-thirds of the coating and the plasticizer comprising less than approximately one-half of the coating, said material being non-adhesive and substantially non-curling when dry, whereby sheets of the material do not block when stacked together 4and do not curl when separated from each other and have quick tack when wetted with water.

22. Sheet material of they character described comprising a backing and on one side of the of dry adhesive and plasticizer in continuous phase containing an elastic resinoid filler in discontinuous phase, the

adhesive comprising approximately one-fourth'4 to three-fourths of the coating and the plashalf of the coating.

23. Gummed sheet material of the water-remoistenable type comprising a paper backing and on one side of the backing an exposed dry coating of water-activatable adhesive and a wain continuous phase and a latex filler in discontinuous phase, the adhesivev comprising approximately one-fourth to three-fourths of the coating and the plasticizer comprising less than approximately one-half of the coating, said material being non-adhesive and substantially non-curling when dry, whereby sheets of the material do not block when stacked together and do not curl when separated from each other and wetted with water.

24. Sheet material of the character described less than approximately onehave quick tack when comprising a backing having an exposed coatrial being non-adhesiveA and substantially noning of dry adhesive and plasticizer in continuous 1 curling when dry, whereby sheets of the matephase` containing an elastic ller in disconrial do not block when stacked together and do tinuous phase, the adhesive comprising approxinot curl when separated from each other and mately one-fourth to three-fourths of the coat- 5 have quick tack when wetted with water.

ing and the plasticizer comprising less than approximateiy one-half of the coating, said mate- CHARLES W. STILI-WELL 

